As for what it will be, it almost certainly will not be like Superman: Escape from Krypton at SFMM. That ride has a huge footprint, it is just long and not very wide. Additionally, I highly doubt Intamin AG will ever build another reverse freefall coaster. If it is a compact launched coaster, it would most likely be more along the lines of SFDK's Superman. However, I've heard elsewhere that the new attraction will not be a new coaster, and will likely be an expansion of Planet Snoopy to give Kings Dominion the most kiddie rides on the East Coast.
Maybe it's going to be the tallest one of those or something.